Flexible polymer tubing can be used as conduits or flow paths to transfer fluid from a source to a desired destination. In some cases, as the fluid is transferred from the source to the destination, other material is added to the fluid. The fluid, with or without added material(s), can also be transferred (e.g., diverted) to multiple destinations such that the destinations have different compositions. As an example, in pharmaceutical manufacturing, a drug from a source can be transferred to a first destination through a flexible tubing. As the drug travels along the tubing, other ingredient(s) can be delivered through other fluidly-connected tubing to combine with the drug, and the resulting combination can be delivered to the first destination. The drug (with or without other ingredient(s)) can be delivered to other destinations by controlling the flow paths of the drug and the ingredient(s). The compositions in these other destinations may be different from or the same as the composition in the first destination.